<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <link rel="stylesheet" href="./css/index.css" />
  <title>记事本</title>
</head>

<body>

  <!-- 主体区域 -->
  <section id="app">
    <!-- 输入框 -->
    <header class="header">
      <h1>小黑记事本</h1>
      <input placeholder="请输入任务" class="new-todo" v-model="username" />
      <button class="add" @click="add()">添加任务</button>
    </header>
    <!-- 列表区域 -->
    <section class="main">
      <ul class="todo-list">
        <li class="todo" v-for="(item,index) in List" :key="item.id">
          <div class="view">
            <span class="index">{{index+1}}.</span> <label>{{item.name}}</label>
            <button class="destroy" @click="del(item.id)"></button>
          </div>
        </li>
      </ul>
    </section>
    <!-- 统计和清空 -->
    <footer class="footer" v-show="List.length!==0">
      <!-- 统计 -->
      <span class="todo-count">合 计:<strong> {{List.length}}</strong></span>
      <!-- 清空 -->
      <button class="clear-completed" @click="clear()">
        清空任务
      </button>
    </footer>
  </section>

  <!-- 底部 -->
  <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
  <script>

    const app = new Vue({
      el: '#app',
      data: {
        username: '',
        List: [
          { id: 1, name: '跑步' },
          { id: 2, name: '睡觉' },
          { id: 3, name: '干饭' },
          { id: 4, name: '打豆豆' }
        ],

      },
      methods: {
        // 点击删除
        del(id) {
          this.List = this.List.filter(item => item.id !== id)  // 找到id删除
        },
        // 清空任务
        clear() {
          this.List = []
        },
        // 添加任务
        add() {
          if (this.username.trim()) { // 确保输入不为空
            this.List.unshift({
              id: this.List.length + 1,
              name: this.username
            });
            this.username = ''; // 添加任务后清空输入框
          } else {
            alert('请输入任务名称'); // 可选：提示用户输入内容
          }
        }
      }
    })

  </script>
</body>

</html>